US Bridges

Monkland Lane over Grass Valley Canyon

Fair

Sherman County, Oregon · 1.2 MI E of HWY 97 · Structure no. 558391062500125

Built
1957
68 years old
Condition
Fair
inspected August 2024
Type
Tee Beam
Concrete Continuous
Length
88 ft
3 main spans
Daily traffic
140
2020 count
Owner
County
County Highway Agency

About this bridge

Monkland Lane over Grass Valley Canyon is a concrete continuous tee beam carrying Monkland Lane over Grass Valley Canyon in Sherman County, Oregon. It was built in 1957, so it is 68 years old, older than the Oregon average of 49.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 140 vehicles a day, roughly 10% of them trucks, projected to reach 150 by 2025. The structure is 88 ft (26.8 m) long and 29 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

CarriesMonkland Lane
CrossesGrass Valley Canyon
Location1.2 MI E of HWY 97
RouteCounty Highway 0
StateOregon
Coordinates45.49362, -120.68539
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.3 US tons
Inventory rating26.5 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length88 ft (26.8 m)
Longest span42 ft (12.8 m)
Deck width29 ft (8.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic140 (2020)
Projected traffic150 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Monkland Lane over Grass Valley Canyon built?

It was built in 1957, making it 68 years old in 2025.

What condition is Monkland Lane over Grass Valley Canyon in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in August 2024.

How much traffic does Monkland Lane over Grass Valley Canyon carry?

About 140 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Monkland Lane over Grass Valley Canyon?

The structure is 88 ft (26.8 m) long with a longest span of 42 ft (12.8 m) and a deck 29 ft wide.

Who owns Monkland Lane over Grass Valley Canyon?

It is owned by the County Highway Agency.